Varying a numerical aperture of a laser during lens fragmentation in cataract surgery

Abstract

Some embodiments disclosed here provide for a method fragmenting a cataractous lens of a patient's eye using an ultra-short pulsed laser. The method can include determining, within a lens of a patient's eye, a high NA zone where a cone angle of a laser beam with a high numerical aperture is not shadowed by the iris, and a low NA zone radially closer to the iris where the cone angle of the laser beam with a low numerical aperture is not shadowed by the iris. Laser lens fragmentation is accomplished by delivering the laser beam with the high numerical aperture to the high NA zone, and the laser beam with the low numerical aperture to the low NA zone. This can result in a more effective fragmentation of a nucleus of the lens without exposing the retina to radiation above safety standards.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of and claims priority to U.S. patent application Ser. No. 14 / 193,740, filed Feb. 28, 2014, which claims the benefit of priority to U.S. Provisional Application No. 61 / 794,359, filed Mar. 15, 2013, the entire contents of which are incorporated herein by reference.BACKGROUND[0002]1. Field[0003]Embodiments of this invention generally relate to laser cataract surgery, and more particularly to a method of laser-assisted lens fragmentation.[0004]2. Description of Related Art[0005]Eye disease can impair a patient's vision. For example, a cataract can increase the opacity of an ocular lens, and eventually, cause blindness. To restore the patient's vision, the diseased lens may be surgically removed and replaced with an artificial lens, known as an intraocular lens, or IOL. A number of medically recognized techniques are utilized for removing a cataractous lens based on, for example, phacoemulsification, mechanica...

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